Hepatitis in children mystery still being investigated as cases rise

British health officials say they are still not clear about the cause of an increase in liver inflammation or hepatitis in children.

A common adenovirus is believed to be involved, but other possibilities are still being investigated.

In the UK, 163 cases have now been identified and 11 children have received liver transplants.

Cases have been detected in 20 countries worldwide, with almost 300 children affected and one death.

“It’s important for parents to know that the chances of their child getting hepatitis are extremely small,” said Dr. Meera Chand from the UK Health Authority (UKHSA).

She said parents should still be aware of the signs – particularly jaundice, a yellow tinge in the whites of the eyes – and that they should contact a doctor if they have concerns.

A further 18 children with hepatitis have been identified in the UK since last week – 118 live in England, 22 in Scotland, 13 in Wales and 10 in Northern Ireland.

The children’s most common symptoms were jaundice and vomiting – and most were under five years old.

The UKHSA’s latest case report says there has been “an apparent drop in confirmed cases” in the UK overall over the past two weeks.

What puzzles scientists is that the most likely cause — the adenovirus — doesn’t usually make children seriously ill. Spread from person to person through coughing and sneezing, it can cause colds, vomiting and diarrhea.

However, it is very unusual for adenovirus to be a cause of severe hepatitis in otherwise healthy children, but it has been circulating at high levels since the beginning of the year after virtually disappearing during the pandemic.

Genetic analysis of samples from some of the children has found a type of virus called AAV-2 – but it doesn’t usually cause disease either, the report said.

Scientists are also watching another type of adenovirus called F41.

“Our research continues to suggest that there is an association with adenovirus, and our studies are now rigorously testing that association,” said Dr. Chand.

“We’re also investigating other contributors.”

These include whether a new variant of the adenovirus has evolved, making children sicker, or whether a previous infection such as Covid could play a role.

Another possibility is that by delaying young children’s exposure to a range of different viruses due to less social mixing, the pandemic may have made them more vulnerable to disease.

UKHSA says there is no evidence linking it to the Covid-19 vaccine as most children with hepatitis were too young to get it.